Everything we said here were just assumptions, while trying to figure out what was causing the problem. Since the last format this error never occured again, but I don't have any backup utility installed at the moment (can't afford to renew the license right now, have to wait until xmas, I just hope my pc won't blow up before). My guess is for a driver compatibility issue, and surprisingly it looks like Windows solves this problem by itself, but I really have no clue when, how and what's causing it. On the other hand, the problem doesn't seem to be harmful, I could always create backups with no errors and everything worked fine. So, you can probably ignore it if System Restores and backups work fine, and maybe one day we'll all be able to figure it out :huh: